Habitat fragmentation can isolate plant populations and disrupt ecological processes essential for reproduction and long-term persistence. Among the key mechanisms driving decline in such contexts are Allee effects, which occur when individual fitness decreases as population size or density declines. Demographic Allee effects limit population growth, while component Allee effects act through specific processes such as reduced pollination or elevated seed predation. Ptilotus macrocephalus (Featherheads), a long-lived perennial forb endemic to the Victorian Volcanic Plain (VVP), now persists primarily in small, isolated remnants, making it a useful system for investigating how Allee effects influence reproduction and persistence in fragmented grasslands.

Reports of low seed production and pre-dispersal seed loss to an unidentified predator have raised concerns about the species’ long-term viability. This study assessed floral visitation, seed set, seed predation, and recruitment across 15 remnant populations spanning a range of sizes and densities. More than half of 45 historically recorded populations could no longer be found in 2024, suggesting ongoing local extinctions. Seed set was low across populations of all sizes, and patterns consistent with multiple component Allee effects were observed, including reduced pollination in low-density floral patches and lower seed predation in larger populations. Controlled pollination treatments did not clarify the breeding system.

Floral visitors spanned a wide taxonomic range, suggesting a generalist pollination system. Thrips were particularly abundant and may act as both pollinators and floral herbivores. Recent recruitment was evident in five populations, each containing more than 120 individuals. These findings suggest that reproductive success in P. macrocephalus is shaped by local floral context, seed survival, and demographic thresholds. Conservation strategies should focus on augmenting small populations (<120 individuals), reintroducing the species to areas of local extinction, and increasing patch density to enhance pollination and support long-term persistence.

Climate change is driving increases in the intensity and frequency of extreme heat events across ecosystems. Exposure to one type of environmental stress can enhance tolerance to both that and other stressors—a phenomenon known as cross-tolerance. In plants, cold priming is thought to confer heat tolerance, likely due to shared physiological responses between these stressors. However, few studies have examined thermal cross-tolerance through the lens of photosynthetic processes, despite their central role in plant metabolism. Further, studies on thermal cross-tolerance have focused on individual crop species, with no investigations into wild species, despite the potential implications for adaptive fitness under climate change. To investigate interspecific variation in thermal cross-tolerance of plant photosystems, we exposed six native Australian plant species to a cold snap, a heatwave, or benign control conditions. Following a one-week recovery period, all plants except those in the control group were subjected to a four-day heatwave. Photosynthetic processes were monitored throughout the experiment, and photosystem heat sensitivity assays were conducted both after priming and following the subsequent heatwave. Our findings indicate that certain aspects of photosynthesis increased under heat priming, while others declined in response to cold priming. Species differed markedly in their physiological responses throughout the experiment, but some responses were unaffected by thermal stress. Photosynthetic health was significantly reduced in the unprimed group during the second heatwave across all species suggesting that pre-treatment improved photosynthetic responses. Interestingly, photosynthetic responses of cold and heat pre-treated plants were similar during the second heatwave across all species suggesting an effect of thermal cross tolerance. This consistent effect of thermal cross tolerance underscores the importance of accounting for multiple stressors when predicting species distribution shifts under climate change.

Competitive plant–plant interactions are shaped not only by direct resource competition, but also by plants’ ability to detect and respond to neighbouring vegetation, influencing both competitive dynamics and species success. Shade avoidance plasticity is a well established response to reductions in light quality that signal upcoming competition. Elongation in anticipation of neighbour shading is a hallmark of this response, and is often treated as a predictable and adaptive strategy that improves a plant’s ability to compete for light. Yet, the expression and benefits of shade avoidance responses can vary, shaped by ecological trade-offs, species specific traits, and the reliability of shade cues.
Using six Brassicaceae species as a model system, we ran a glasshouse experiment to examine how plants varying in size and growth form respond to anticipatory light quality cues and competitive stress, and whether trait plasticity aligns with expectations of adaptive shade avoidance. We quantified morphological and phenological trait responses throughout development and measured reproductive outcomes. Results show that cue-response relationships depend on competitive context, and can vary unpredictably across related species. Only some species showed clear elongation responses, and in many cases, this plasticity did not translate into improved performance when grown with competitors. These results challenge the generality of shade avoidance as a reliable, adaptive strategy for competition, suggesting that its ecological consequences for community composition and species coexistence may be less predictable than often assumed.

Abstract: Alternative and Innovative Habitat Alternatives for Native Wildlife

As global ecosystems face increasing pressures from urbanisation, climate change, and habitat fragmentation, the conservation of native wildlife demands adaptive and forward-thinking strategies. This discussion explores the development and implementation of innovative habitat alternatives designed to support the survival and well-being of native species in rapidly changing environments including construction that causes displacement Drawing on interdisciplinary approaches—spanning ecological design, biomimicry, and sustainable engineering—this research investigates both naturalistic and artificial habitat structures, including, wildlife corridors, and modular shelters tailored to specific species needs. Emphasis is placed on enhancing habitat connectivity, promoting biodiversity, and ensuring ecological functionality. Pilot projects and case studies demonstrate the feasibility, ecological value, and community integration of such alternatives. By reimagining habitat creation through innovation and inclusivity, this work contributes to a resilient framework for wildlife conservation.

Tropical forest transpiration is a key component of the global water cycle and is generally estimated through in situ sap flow measurements across tree species and size classes. The role of crown exposure on sap flow variation has been poorly explored in cyclone-prone tropical forests, despite relatively frequent canopy disturbances. Here, I present a study investigating the role of crown exposure on sap flow variation in a common sub-canopy tree species of the cyclone-prone Daintree Rainforest. Taking advantage of the SuperSite infrastructure at the Daintree Rainforest Observatory (DRO), we asked: (1) How much does sap flow vary within a species? and (2) How do crown exposure (measured from the DRO’s canopy crane), sensor position (north vs. south), and environmental conditions influence sap flow variation within trees? We monitored sap flow on the north and south aspects of 10 similarly sized Myristica globosa subsp. muelleri trees during three campaigns (peak dry and wet season conditions in 2023 and 2024). After the first campaign, the forest was impacted by Tropical Cyclone Jasper, enabling a natural experiment to assess the role of cyclone-induced changes in crown exposure. Across all trees and seasons, maximum sap flow ranged from 2 to 23 cm/h, revealing a tenfold within-species variation despite similar DBH. North-south sap flow differences were inconsistent across trees but showed a population-level pattern in the dry seasons: higher north-aspect flow pre-cyclone and higher south-aspect flow post-cyclone. These shifts corresponded with a doubling in crown exposure pre- and post-cyclone due to canopy thinning of neighbouring trees and were driven by radiation. This study identifies pronounced within-species and within-tree sap flow variation and presents the first evidence that cyclone-driven crown exposure changes can significantly alter transpiration estimates. These findings underscore the importance of accounting for canopy structure and disturbance history in model-based estimates of forest transpiration.